The semiconductor fabrication industry requires materials and deposition technology adequate to deposit metals, metal mixtures and metal compound mixtures in thin layers, plugs, vias, and patterns on semiconductor and insulating or dielectric substrates to make appropriate electrical devices for integrated circuits, memory devices and flat panel display devices.
Various techniques are known for depositing metals, metal compounds and their mixtures on appropriate electronic materials substrates, including; physical methods sputtering, molecular beam epitaxy, evaporation and laser ablation, alloying, and chemical vapor deposition (plasma, photo or laser enhanced).
Chemical vapor deposition (CVD) has gained favor in recent years due to its properties of providing uniform and conformal deposition and its ability to deposit an array of materials under highly controllable conditions. Typically, chemical vapor deposition can provide high deposition rates of high purity materials in a controlled fashion.
Zirconium and hafnium oxynitride gate dielectrics and zirconium and hafnium silicon oxynitride gate dielectrics have been generated by multiple processes, e.g., sputter deposition, plasma deposition, and electron-beam. These gates afford higher dielectric constants than conventional thermal silicon oxide or silicon dielectric layers and they may be thicker.
Representative articles in the prior art illustrating the formation of zirconium and hafnium metal films, zirconium and hafnium oxynitride and zirconium and hafnium-silicon oxynitride dielectrics are as follows:
U.S. Pat. No. 6,503,561 discloses a thermal CVD process for the deposition of multiple metal layers on a substrate from a solventless mixture of two or more metal ligand complex precursors, e.g., zirconium, hafnium, aluminum, germanium, etc. where the ligand is selected from the alkyls, imides, amides, halides, nitrates, fluorine, by direct liquid injection to a flash vaporization zone and the solventless mixture is mixed with oxygen prior to deposition of the multiple metal compound layer.
U.S. Pat. No. 6,291,867 discloses the formation of hafnium and zirconium silicon-oxynitride gate dielectrics by plasma deposition. One process includes the plasma deposition of a zirconium silicide on a substrate, annealing in an atmosphere including oxygen and nitrogen, e.g., NO. In another method, the silicon silicide layer is annealed in a non-oxidizing atmosphere including NH3 or nitrogen and then annealed in an oxidizing atmosphere. A CVD process is disclosed for forming the silicide layers.
The article, Thermally Stable CVD HfOxNy Advanced Gate Dielectrics With Poly-Si Gate Electrode, 2002 IEEE 0-7803-7463-X/02/$17.00 (C) discloses the formation of HfOxNy layers wherein a tetrakisdiethylamino hafnium precursor with N2 carrier gas and ammonia is deposited by rapid thermal CVD followed by post deposition annealing at 800 to 900° C. In the process, the HfOxNy is grown at a temperature of from 700 to 800° C.
In a comparison example, HfO2 was deposited at 500° C. using O2 and the same precursor followed by post deposition annealing.